From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934443AbZHEOF2 (ORCPT ); Wed, 5 Aug 2009 10:05:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934124AbZHEOF1 (ORCPT ); Wed, 5 Aug 2009 10:05:27 -0400 Received: from mx2.redhat.com ([66.187.237.31]:53054 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933639AbZHEOF1 (ORCPT ); Wed, 5 Aug 2009 10:05:27 -0400 Date: Wed, 5 Aug 2009 10:04:08 -0400 From: Neil Horman To: "Eric W. Biederman" Cc: Amerigo Wang , linux-kernel@vger.kernel.org, tony.luck@intel.com, linux-ia64@vger.kernel.org, akpm@linux-foundation.org, Ingo Molnar , Anton Vorontsov Subject: Re: [Patch 0/7] Implement crashkernel=auto Message-ID: <20090805140408.GJ7259@hmsreliant.think-freely.org> References: <20090805112123.6552.73574.sendpatchset@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 05, 2009 at 06:33:57AM -0700, Eric W. Biederman wrote: > Amerigo Wang writes: > > > This series of patch implements automatically reserved memory for crashkernel, > > by introducing a new boot option "crashkernel=auto". This idea is from Neil. > > > > In case of breaking user-space applications, it modifies this boot option after > > it decides how much memory should be reserved. > > > > On different arch, the threshold and reserved memory size is different. Please > > refer patch 7/7 which contains an update for the documentation. > > > > Note: This patchset was only tested on x86_64 with differernt memory sizes. > > This seems like a silly hard code. Especially for a feature distros don't > care enough about to implement a working initrd for. > > Has anyone bothered to justify those large amounts of memory? > Where does the 128M go? > > Please pardon me for being a cynic but I don't see the command line option > being the bottleneck for real users to make this work. > > Eric Lots of the impetus behind this results from a desire to have kexec configured and setup up during install. Having the kernel allocate a default size block of RAM lets you do that without the need for an interim reboot. You could of course boot the installer kernel with a crashkernel line pre-selected suppose, but then you have to go to the trouble of figuring that allocation size out each time. This gives you a nice convienent way to get a reasonable block of memory without the need to do all that extra work. Neil